


The Price of Memory

by toastycyborg



Category: Fallout 4, ワンパンマン | One-Punch Man
Genre: Amnesia, Blood, Crossover, Cussing, Fallout 4 AU, M/M, Romance, Slow Burn, Spoilers for Fallout 4, Violence, canon minor characters - Freeform, fallout context included in footnotes
Language: English
Status: In-Progress
Published: 2017-11-25
Updated: 2017-11-25
Packaged: 2019-02-06 19:54:49
Rating: Mature
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 4,234
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12824910
Author URL: https://archiveofourown.org/users/toastycyborg/pseuds/toastycyborg
Summary: Boston, 2287. Saitama works for the Railroad, an underground movement that frees enslaved synths from the mysterious "Institute". Despite his incredible strength and speed - a mutation from nuclear fallout - Saitama is bored. He feels nothing, indifferent in a post-apocalyptic world.An encounter with GN-05, an Institute synth assassin, doesn't end the way he expects. In the aftermath, Saitama does what he does best: he saves the synth. In time, maybe "Genos" will find a way to repay his debt.





	The Price of Memory

**Author's Note:**

> _One Punch Man_ and _Fallout 4_ , and all of their characters therein, are property of ONE and Bethesda Game Studios respectively. No copyright infringement is intended in this fanfiction.

**Notes for the Chapter:**

> beta'd by the-nysh. Thanks a million!
> 
> Fallout 4 takes place in a post-apocalyptic world, following a devastating nuclear war. It is a dark world with dark themes. Reader discretion advised.

 

Trudging through a thunderstorm was not Saitama’s idea of a fun night.

Grit crunched underfoot as he stopped outside the old West Everett Estate. Broken mailboxes shone in the downpour, decrepit cars and sandbags piled up like a barrier around the settlement. The rain was deafening, like minigun-fire off the rusted vehicles. The buildings barely held themselves together, a fortified but deserted speck of downtown Boston that reeked of burnt meat and rubber. Firelight flickered in empty windows, cast by barrels set aflame. Picket fences lay smashed, an American flag left to rot on the drowned concrete.

It must’ve looked nice before the bombs fell, Saitama thought. Two hundred years of post-nuclear neglect would do that to a suburb.

He squinted through the deluge, soaked to the bone in his greaser jacket and jeans. No human had dwelled here in decades, yet he could still make out more recent signs of life. A crude campfire and cooking spit had been thrown together near the entrance, raised spotlights pivoting in search of intruders. Then, there were the bodies – not a rare sight in the Commonwealth – dead Raiders and animals strewn on the ground. The carcasses looked semi-fresh, killed less than a week ago.

The most telling sign was a net of bloody gore, strung like a piñata from a lamppost in the middle of the street. A flash of lightning threw it into sharp relief, casting ominous shadows on the tarmac.

Something nasty lived here now.

Saitama’s mission was simple. It always was with the Railroad, at least for a Heavy like himself: head to a location, take out anything hostile, leave. His job was to secure the other agents’ routes, so they could move their packages safely.

“Time to clear the train tracks,” he muttered. With a smirk at his own little joke, Saitama – unarmed – started forward.

He made no effort to be quiet. He stepped in puddles, kicked at rubble, rapped on the crumbling forklift that half-blocked the gap in the makeshift wall around the estate. There was no reason to be stealthy; he felt it easier to lure the residents out, let them come to him. Sure enough, the noise drew movement from inside the houses – grunts and heavy footfalls. As the closest spotlight swivelled to illuminate him, the door to the house on Saitama’s left burst open.

A Super Mutant lumbered out, sledgehammer in hand. It was grotesque, seven or eight feet tall, fat muscles bulging under dirty green skin. Its beady eyes locked on Saitama and it bellowed a battle-cry, and began to charge straight at him.

Saitama shielded his eyes from the dazzling spotlight. As the monster thudded closer, four of its brothers emerged from around the neighbourhood. Each was uglier than the next, monstrous brutes. They jeered in rough voices, armed with spiked boards or pipe rifles, eager to feast on the ‘puny human’ who had stumbled into their home.

They’d been human themselves, once, twisted into hulking freaks by sick experiments. A Forced Evolutionary Virus – FEV – had traded their brainpower for endurance and terrible strength, which made fighting them generally unpleasant.

At least, it did for most people.

The charging Mutant swung its sledgehammer high, and brought the massive weapon down on Saitama. Saitama didn’t blink, didn’t flinch – but raised his non-dominant hand, and caught the blow in his palm.

He stopped the attack cold, killed its momentum without effort. The ground at his feet cracked from the weight of it. The Mutant stumbled, dumbstruck, unable to work out why he wasn’t a bloody smear on the concrete.

Before the brute could react, Saitama balled his free fist.

Bare-knuckled, he threw a lightning-fast uppercut to the Mutant’s jaw. Its head snapped back in a spray of spit, neck broken. The force of his punch knocked the monster flying, sent its corpse arcing limp through the air. The hammer was ripped from its grasp, still buried in Saitama’s palm.

The Mutant hit the dirt hard, ten feet from where it had been standing. As the dust settled, Saitama let the sledgehammer likewise thud to the pavement. He was something of a freak himself.

The monster’s brothers roared in shock and confusion. Enraged by the small man’s impossible strength, they opened fire.

Saitama dived. He ducked behind the forklift, sneakers slick on the wet ground. Though hardier than the average man, he wasn’t immune to a hundred bullets all racing toward him at once. The hail of shots pinged off his rusty hiding place, sparks snuffed by the rain. One bullet glanced by his face and he swatted it from the air like a wasp, but didn’t lose his cool.

At a pause in the noise, he heard a second melee Mutant storming toward him. Still calm, almost indifferent, Saitama circled the forklift to take his foe out from behind. His swift strike dropped the creature to its knees, and he was back in cover before its face could smash into the dirt.

The last three Mutants posed no greater challenge. He darted from one enemy to the next, dodging shots and vaulting debris, and took them each down with a single blow. They crumpled like marionettes with severed strings, dead before they even knew he was there.

As the last body crashed flat, the hiss of rain swelled in the restored silence.

Saitama straightened up. Water rolled down his bare scalp and leather jacket, dripped from his nose to the rumble of distant thunder. His stance unwound, shoulders going slack as he surveyed the damage he’d wrought. New cracks split the walls of the surrounding buildings, craters born of the shockwaves from his fists. Nearby trashcans had been shunted aside, burning barrels extinguished.

Saitama sighed. Resigned, he stepped over the Mutant corpses and began to search the homes for supplies.

The brief battle had sharpened him a moment, but he’d felt no excitement. No thrill, no rush, no sense of danger – none to him, at least. Instead he felt hollow, detached. He wouldn’t even have called it a ‘fight’, not really: it was a routine, a chore, soul-crushingly tedious.

It was hard to work up a sweat when one could punch through steel, and bend girders like chicken wire.

A little over two hundred years ago, nuclear war destroyed the world. The radiation affected everyone to this day, still altering people’s genes two centuries after the bombs fell. Most folks, it made sick: cancer, sterility, weak bones and the like.

Saitama was different.

Being born and raised on irradiated soil, he’d lost his hair at a young age. This wasn’t so unusual. What _was_ unusual was the absurd, superhuman strength and speed he’d developed at the same time.

At first, he’d used his mutation to protect settlers from scavengers and Raiders. He stopped assaults and shakedowns, drove zombie-like feral Ghouls from the pitiful towns people had cobbled together. As he aged from boy to man, and his strength grew, Saitama had been able to take on more powerful enemies. Gunner mercenaries. Super Mutants. Deathclaws.

Good as it felt to help those who needed him, Saitama learned a sour truth very quickly.

The stronger he got, the less he felt in battle. These days, there wasn’t a creature alive which he had to put effort into fighting. Without a challenge, his amazing strength stopped being so amazing. It became dull, mundane … boring.

Over time, this lack of passion bled into the rest of his life. He struggled to empathise with ‘normal’ folk, didn’t know their woes. Sometimes they thanked him when he saved them from danger, but not always. Most of the time, they were scared. Scared of _him_ , of his power, suspicious it was all a scam. They treated him like a freak despite his heroics, never missed a chance to chew him out for collateral damage or tardiness.

He didn’t care. He didn’t help them for praise: he did it because he wanted to.

By the time he hit his twenties, Saitama barely felt anything anymore. Excitement, pain, nothing. He left home to travel the Commonwealth, roamed in search of something – _anything_ – that could give him a real fight. He still helped folk along the way, of course, passers-by in trouble, but he never stuck around afterward.

The Railroad had reached out to him a few years ago. He couldn’t remember exactly when or how it happened, but it did. They were an underground movement, freedom fighters. They said they respected his power, and valued his wish to save lives.

They opened his eyes to a real injustice in the world, a wrong they needed his incredible strength to put right.

Emerging from the last dilapidated house, Saitama pocketed the box of snack cakes he’d scavenged. His task tonight was to clear the path for another Railroad agent, one who would escort a liberated synth out of the Commonwealth.

 _Synth_. The word still made him pause in wonder.

Synths were synthetic people, advanced machines created by the Institute. The latest generation of synth, ‘gen-3’s to the Railroad, were sentient, aware. They looked and thought and acted just like humans, indistinguishable from the real thing. For all intents and purposes, they _were_ human – but their creators in the Institute treated them like slaves. The Institute wasn’t above wiping a synth’s mind when it disobeyed, and stopped at nothing to hunt down any who managed to escape.

When the Railroad asked for Saitama’s aid in freeing these abused androids, he’d joined up without a second thought.

Helping regular people didn’t move him, but synths were another story. They were innocent, mistreated, ‘born’ into servitude. Those unlucky enough to have full awareness were miserable, suffering every day and unable to help themselves. Saitama couldn’t ignore the Institute’s cruelty; he believed gen-3s deserved the same rights as humans, deserved freedom and a shot at a normal life.

Working with the Railroad, Saitama felt like he had a purpose.

Battered by rain, he glanced around the abandoned estate. Since no new Super Mutants had appeared while he’d been looting, he deemed his job done. The route was clear. All that remained was to return to headquarters, and let his boss know it was safe for the Runner to move their ‘package’.

He stepped over a lawn flamingo and onto the main road, thoughts already drifting to the lumpy mattress that awaited him back at HQ.

Lightning struck the ground behind him.

Blue light burst through the estate. The shockwave knocked Saitama forward: it scorched the pavement, ripped the air like a blast from a plasma rifle. Saitama whirled as he stumbled, turned – in time to watch an Institute synth materialise inside the bolt.

It was an old gen-2, grey plastic skin on a mannequin-like body. Robotic, not _aware_ , a true machine. It appeared out of nowhere, spat onto the cracked road by the rush of electricity. The android cocked a blocky laser pistol as the ‘lightning’ faded, and fixed its glowing yellow eyes on Saitama.

It wasn’t lightning. He’d seen it before: it was the beam of the Molecular Relay, the teleporter the Institute used to move their soldiers.

Another fiery-blue flash, and a second identical synth appeared beside the first. Before Saitama could react, a third beam of energy lanced from the sky to the concrete – but the final synth it ejected looked very different from the previous two.

From its porcelain skin and choppy blond hair, Saitama knew it was a gen-3. Humanoid, male – and aggressive, if the scowl on its face was anything to go by. Oddly for a gen-3, which were built to look as realistic as possible, it shared the older models’ yellow-on-black eyes. Unlike the gen-2s, though, this synth wore clothes: an armoured grey coat, tall boots, and leather gloves.

Saitama recognised the uniform as that of a Courser, and he swallowed hard. Coursers meant business. They were the Institute’s elite, assassins.

The Courser levelled its rifle at him, and spoke in a deep baritone. “Target acquired.”

Saitama dived.

He ducked back into the house, took cover indoors as hot plasma obliterated a chunk of nearby fence. Spine pressed to the wall, he heard movement: metal feet in approach, the thrum of energy weapons. No time to think, he threw himself forward. He weaved through the dilapidated rooms, ran with head covered as laser gunfire shredded the walls.

The gen-2 synths stopped shooting. They advanced, vaulted the charred fence. One followed their target indoors. Saitama huddled beside an empty fridge, hid while the synth swept its pistol about the dark interior.

It spoke, voice a synthesized monotone. “ _Visual contact lost. Searching._ ”

Outside, the Courser lowered its weapon. It stood and observed, scowl unbroken as rain flattened its hair. In silence, it watched the other gen-2 jog to cover the back door.

Saitama heard its approach, and sighed. Same old Institute tactics.

In a great crash of wood, before the androids could box him in, Saitama shouldered his way out through a side wall. He kept low and circled around the house, just like he had with the Super Mutants earlier. His plan now was the same as then: to take his opponents out from behind, one by one. Calm, he set his sights on the oblivious synth guarding the back door.

The Courser appeared, in his face so suddenly that later he’d swear it teleported.

Saitama swerved in alarm but the Courser somehow stayed in front of him, _kept up with him_. He didn’t even see it move. Mild shock pinged in his mind – shock that exploded at the force of the gloved punch that caught him in the nose.

Saitama reeled, skidded on his heels until he slammed into a flaming barrel. Before he could work out what happened, nose throbbing, the Courser attacked again – made to strike him with the butt of its rifle. Saitama dropped flat, kicked his assailant’s legs out from under it. The blond synth fell to the mud with a grunt, firearm slipping from its hands. Saitama hopped up. He snatched the weapon from the puddle into which it had fallen, and threw it as hard as he could across the estate.

By the time he turned around, the Courser was already back on its feet. It tackled him, rammed a shoulder into his middle and knocked him down again. They rolled together through the filth, grabbing at each other to try and gain the upper hand. As powerful as he was, Saitama couldn’t pin his opponent down.

This was no ordinary Courser.

The gen-2s arrived around the sides of the house, pistols hot. Their haphazard shots forced Saitama and the Courser to scramble apart, and Saitama ran. He charged across the street and into the side-alley of another house, vaulting a toppled grill as plasma ate into his surroundings. He heard the Courser on his heels, felt the breeze from its hand as it made a wild grab for his jacket.

Mid-dodge, Saitama couldn’t help but smirk. This was it – a _real_ fight. He didn’t care why the Institute had sent a hit-squad here, to the outskirts of downtown Boston. It didn’t matter. He felt his blood pump faster for the first time in years, tasted the salt of sweat on his lip. The rain burned cold on his bald head, body heating up from exertion.

 _This_ was what he’d been waiting for.

He ducked under the veranda of the second house, grabbed its mailbox in passing and wrenched it up from the earth. Still running, Saitama whirled on his heel and threw the mailbox at the closest gen-2. His makeshift projectile hit its mark, smashing clean through the synth’s abdomen. Its body was severed at the waist in a spray of gears and tubes, and the defeated synth fell to the ground in two pieces.

Saitama didn’t stop, but bobbed as the Courser swung again for his head.

Disarmed of its rifle, his pursuer used its own body as a weapon. It attacked recklessly, stayed in close quarters. After another near-miss, Saitama threw a punch of his own. His knuckles grazed the Courser’s cheekbone, knocking loose strands of its hair. The synth didn’t pause, didn’t even seem to notice, its assault relentless. Evading the counterattack, Saitama punched again – minimal force, curious how much damage it could take. This time, he struck his foe square in the shoulder.

The _crack_ under his fist was metallic, not the telltale snap of bone he expected of a gen-3. The Courser skidded from the blow, clutched its injured joint, but didn’t give in. It flung itself at him again – no hesitation, grunt of pain, or fear of further injury.

This thing didn’t know when to give up, Saitama thought.

Through the corner of his eye, across the yard, Saitama saw the remaining gen-2 train its pistol on him. “ _Unit: GN-05, in danger. Defending_.”

The gun flashed. Saitama seized the Courser by the front of its coat, and swung it around to use as a shield. A plasma round glanced off its armoured back, blue flames sizzling in the rain. The Courser knocked Saitama’s hands away at once. In the same movement, it brought up a leg. It kicked him hard in the chest, sent him stumbling. Saitama bounced off the wall of the house, used it as a spring-board to propel himself out of the alley and back onto the main street.

He wanted to fight the Courser one-on-one, no distractions.

He made a beeline for the last gen-2. It stood in the road, beside an old pre-war car. The vehicle was corroded but not destroyed, fusion-powered, highly flammable. The synth kept shooting as he raced toward it, too slow to land a hit. Saitama took it down with one strike, the punch so hard that he knocked off all but one of its limbs.

Again, with the Courser still hot on his heels, Saitama didn’t stop. He half-jumped, half-slid over the car’s rain-slicked bonnet – but tripped on the broken pavement once he cleared the vehicle. He lost his balance, just long enough for the Courser to catch him.

It seized him by the jacket, wrenched him around, and slugged him in the face before he could duck. The heavy hit stunned Saitama a moment, drove him to all fours beside the car. Dazed, he spat out a daub of blood from where his teeth had cut the inside of his cheek.

The Courser towered over him, dripping wet while its dislocated arm hung limp from its socket. The sight would have intimidated any other person. Instead, Saitama’s gaze slid to focus on movement behind his attacker.

On the flooded pavement, the second gen-2 dragged itself closer to its fallen pistol. Only its head and right arm remained attached to its body, disabled but still online. As Saitama watched, it collected the weapon from the ground. It took shaky aim at him, around the Courser, and began to squeeze the trigger.

On instinct, Saitama rolled behind the car. In a great screech of metal, the Courser kicked the vehicle aside – right into the path of the gen-2’s shot.

Fire bloomed on the yellow paint, spread as if the chassis was doused in oil. With a hissed “fuck!”, Saitama scrambled to retreat. Unaware of the danger, its back to the ravenous flames, the Courser chased him. Panicking, Saitama spotted a tyre wall beside the bare bones of a nearby house.

He just had time to dive behind it before the car exploded.

The Courser, on the other hand, wasn’t so lucky.

It was blasted off its feet, flung clean over Saitama’s hiding place in the rush of heat and force. It crashed through a nearby fence and rolled like a violent skipping stone, only coming to rest when it struck the burned-out husk of another car. The Courser fell still, facedown, unmoving in the weeds and rubble.

As the small mushroom cloud dissipated, smelling of ozone and acrid smoke, Saitama straightened up. Breathless, a shrill whine in his ears, he stared around. The second gen-2 had been destroyed in the fireball, residual flames snuffed by the persistent rain. Saitama shook water from his eyes, wiped embers and flecks of ash from his jacket.

That was close.

More from curiosity than anything, he approached the Courser. It hadn’t moved, statue-still where it lay. The back of its coat was ripped and scorched, half-melted, smouldering where raindrops hit the cinders. Cautious, Saitama wedged the tip of one sneaker between its hip and the sodden earth. The synth didn’t react when he flipped it onto its back, neck limp and eyes closed. Blood matted its hair, pooled in the puddles where it trickled from a head wound Saitama couldn’t see at this angle.

It looked dead.

Saitama’s mood soured at the thought of not being able to fight it one-on-one. He let out a heavy breath, and sank into a squat beside the synth. With the frenzy of battle over, he took a moment to examine it more closely.

It was a handsome model, he thought. He’d never seen anything quite like it. It looked young, designed like a guy in his late teens, face all sharp angles and _mood_. He noticed studs in its ears, followed the jut of its throat down to the lip of its coat collar.

Silver glinted there. A necklace? Intrigued, Saitama shuffled in place and reached to hook a finger into its collar. Coursers had no use for accessories. Few people did, these days.

Pulling down the stiff cloth, Saitama uncovered something he didn’t expect at all.

The synth’s porcelain skin ended where a human’s clavicles would’ve been. Below it, there was metal. _Lots_ of metal – but not the flimsy skeletal frame of a gen-2 or older. The Courser’s body looked futuristic, interlocking plates and cables, polished to a chrome finish. Fascinated, Saitama ripped open its coat. The panels roughly mimicked human musculature, gleaming where the rain slid off the curves and grooves. Saitama couldn’t help but touch, traced his fingers over what looked like cooling vents in its chest.

“Holy shit,” he muttered. “What the hell were you, dude?”

When Saitama reached to touch its face, the Courser came back online with a gasp.

The noise it made was awful, neither human nor synthetic, like the howl of a wounded dog. Saitama kicked away, fell onto his rump in shock. He watched with wide eyes as the synth clawed blind at the tarmac, watched its back arch up and go rigid. It coughed, choked on the rain, whined with teeth bared in the small pool of its own blood. Then, its body went slack again – sagged flat – and it began to pant. Its wheezes came ragged, shallow, as if unable to breathe right.

Swallowing hard, Saitama shifted onto hands and knees. The Courser didn’t seem to know he was there, eyes scrunched shut. Wary, he crawled closer.

He didn’t know what to do.

If this were any other synth, he’d help it without hesitation. But it was a _Courser_ – an assassin. It served the Institute, a soulless killing machine. The Railroad feared them; most ran at the sight of one. They would’ve told him to finish the job, to take it offline for good before it recovered and attacked again.

But….

Something was different. _It_ was different. When he’d broken its arm, this synth hadn’t shown pain. Coursers were stripped of things like that. Their training dulled their ability to feel. Now, though, pain looked to be the only thing this one could process. It was hurt, as vulnerable and helpless as any other synth Saitama had saved.

While he dithered, the Courser opened its eyes.

It stared around, disoriented, and groaned as if seasick. Its yellow-black gaze found Saitama, and it tensed where it lay in the dirt. Saitama expected that scowl to return, expected it to glare at him defiantly or challenge him to finish it – but it didn’t. Instead, its agonised expression twisted into something frightened and desperate.

It tried to speak. Saitama couldn’t understand the broken words, but he didn’t need to. It was trying to ask for help, pleading for its life. The synth gave a weak cough and faced away, allowed him a better view of its head wound. He saw right into its cracked skull, saw a slice of brain and a broken microchip embedded in it. Saitama’s stomach turned and he pressed a palm to the injury, stemmed the blood flow.

Mouth dry, he made up his mind.

No other Courser he’d fought had begged to be saved. Their training was supposed to stamp out any fear of death. This one had acted the same at first, but the explosion must’ve knocked something loose in its head. Amnesia, maybe, internal trauma, brain damage. Saitama didn’t care. This guy was still a synth, Courser or not … and right now, he needed help.

With great care, Saitama slid one arm under the backs of the Courser’s knees. The other, he snaked around its shoulder blades. Gentle as he could, he lifted the synth into a bridal carry. The synth seized Saitama’s leather jacket in alarm, long legs and broken arm trailing limp, but soon relaxed. Barely audible above the pouring rain, it managed a strained word of thanks.

“It’s okay,” said Saitama. He turned on the spot, used the houses to orient himself toward North Boston. “I gotcha, kid. You’re gonna be fine.”

 

**Notes for the Chapter:**

> In this story, Saitama is not quite as strong as in OPM canon. He is still incredibly powerful and resilient, but cannot (for example) split stormclouds with his punch. He can probably shrug off one or two bullets, but isn’t totally indestructible.
> 
>  **The Commonwealth** was an administrative division of the New England pre-War American state of Massachusetts. After the Great War of 2077, in which four atom bombs dropped across the USA, the Commonwealth (and the rest of the former United States) was reduced to a “war-ravaged quagmire of violence and despair”.
> 
>  _Fallout 4_ contains several factions. **The Institute** serves as the primary antagonist, unless sided with. They operate in secrecy, creating synths as slaves or infiltrators. **The Railroad** works to liberate these sentient synths, believing in equal rights and freedom.


End file.
